Crystal and molecular structure of a 1 : 1 bullvalene–silver tetrafluoroborate complex

Abstract

The crystal structure of a 1 : 1 bullvalene–silver tetrafluoroborate monohydrate has been determined by X-ray methods on photographic data. The crystals are monoclinic with a= 8·49, b= 14·84, c= 18·74 Å, and β= 107°40′. The space group is P2₁/c with Z= 8. The structure has been refined to a conventional R-factor of 0·12 on 2165 observed reflexions, incorporating individual anisotropic temperature factors for the silver ions and the atoms of the fluoroborate anions. The structure consists of irregular spirals of alternating bullvalence molecules and silver ions, which are also covalently bonded to water molecules. The water molecules form weak hydrogen bonds to the fluoroborate anions. There is no evidence for valence tautomerism occurring in the crystal. Some correlations between the position of the silver ion with respect to the double bond and the Ag⁺⋯ CC distances are presented.